How Giant Viruses Work

An artist's rendering of a Mimivirus (left) compared with the bacterium Escherichia Coli (center) and an average virus (right).

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The alarm began in 1992 with the accidental discovery of the world's first giant virus, known as Mimivirus. It was so large that scientists originally thought it to be a pneumonia-causing bacterium [source: Wessner]. "This really turned the world on its head," says Wilhelm of the scientific community's response to the discovery.

Then, scientists discovered a new giant virus in the Siberian permafrost in 2014, after roughly 30,000 years deep in slumber. Once put in contact with amoeba, the virus, known as Pithovirus sibericum, invaded amoeba like a kid attacks birthday cake. Fortunately, the researchers were able to determine that the virus cannot infect animals or humans, much like their other giant virus brethren [source: Sirucek]. Phew.

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This discovery has since raised concerns that more ancient viruses will eventually be unleashed on the world, thanks to the effects of global warming. "They've done an interesting study," remarks Wilhelm. "It adds some new perspective on different viruses that are out there and the possible genes they could contain, but I think the environmental implications of permafrost thawing are much bigger concerns," he says.

These giant viruses have been around longer than humans (practically rubbing elbows with us, in fact), but modern science only just managed to "discover" them. "We've been living with them for probably hundreds of millions, if not billions of years," says James L. Van Etten, Ph.D. with the University of Nebraska and the Nebraska Center for Virology. "They've been out there all this time."

So thawing permafrost is an issue, just not for the reason many people think, at least in the current view of some experts. The environmental effects of global warming are more of a hazard than the fear of some Neanderthal disease being newly unleashed to the world.

Still, all these assurances aren't going to completely quell the fears of the general public in regard to giant viruses, although a less scary-sounding name probably would have helped the case. So how did these viruses get so big?